1. Field of the Invention
The invention relates to the field of ferrous metallurgy, and more particularly to a method for preparing a vanadium-nitrogen alloy free of conglutination and oxidation after sintering.
2. Description of the Related Art
Typically, the following two methods are employed to manufacture a vanadium-nitrogen alloy. One is to employ a pusher kiln for continuous manufacturing of a vanadium-nitrogen alloy. The method involves high production costs and large energy consumption. And during manufacturing, the temperature rise, the temperature fall, and the maintenance each takes about one month. Thus, the manufacturing time is only about 8 months one year, with low efficiency. The other method is to adopt a shaft kiln heated by medium frequency. For example, vanadium pentoxide or vanadium trioxide, and carbonaceous reducing agent or graphite, are employed as raw materials to prepare balls. The balls are put into a medium frequency induction furnace for reduction for between 2.5 and 3.5 hours in the presence of nitrogen having a flow rate of 10 m3/H, at 1350±100° C., and a vanadium-nitrogen alloy is obtained. However, the sintered vanadium-nitrogen alloys conglutinate with each other and thus cannot fall automatically into the storage chamber. Thus, the manufacturing cannot be conducted continually. After each feeding, the temperature rise and temperature fall must be conducted again. The method has high production cost, high energy consumption, and low efficiency.